Answer:
about 21.43 i hope this helps!!! :)
Step-by-step explanation:
1.42857143 is equal to 1 and 3/7
multiply that by 15
21.4285714286
Think about it. The area (the two dimensional version of volume) of a two dimensional shape, like a square, can be 2 feet by two feet. Multiply these together, and you get 4 feet^2, or four feet squared, This is because in order to get the volume, you multiply the base times the height, one side by the other. You make the feet "feet squared" because you are also multiplying the measurements together, too. In three dimensional shapes though, you have three different ways to go. You have the base, the height and the width beyond it. So you multiply them together and get 8 feet^3 or 8 feet cubed (you multiply three measurements together).
If the series is made up of numbers in an arithmetic progression, you have
where
is the first term and
is the common difference between terms.
Since the last term in the series is
, you have
Solve the system
and you'll find that the first term is
(with
).
